my autistic brother, help!

my brother was claimed to be born autistic. my mother didn't have any dental work, or any injection while she was pregnant with him. as a baby he was normal baby but then my mother got manic depressive and went to mental hospital. my brother was rised by my grandparents. when he was 5 months old the pediatrician sent a letter to my parents that they didn't give him any vaccine yet. so he got all of his vaccines at age 5 months: DTP and oral polio (it happened at year 1978) when my mother returned home she claimed the baby wasn't same like before: crying crancky baby. he would cry for endless hours. also had alot of ear infections.

my brother, now a strong bulky tall 5.11 guy.

his symptoms include: uncontrolable urge to drink water all of the time. he could stand by the fountain and drink nonstop until throwing up, if nobody stops him before. he also eats pickles and drinks the pickle liquid. he can eat hot peppers without any grimace. actually to pop them into his mouth one after one like popcorn. he loves to eat nuts, cracking them with his teeth and he could end up eating whole heaps of nuts... He self injures him by picking on pimple he might have on the face into a bleeding wound. he scratches and scratches it nonstop. also pulls at his hair if it gets too long, so we must shave him so he doesn't get a pull his hair from his scalp.

he gets temper tanturms that he throws things, bites himself at his right hand, screams, runs... to restrain him, 4 strong men needed to hold him down!
he obsesses over things, and every while he changs his obsesion to other:
he used to obsess to make puzzles that had thousand pieces. then he wasn't interested at it anymore, so he would eat the puzzle pieces. also used to obsess into pulling threads from fabrics. pulling thread after thread until the fabric disloved into handful of threads. if it didn't go as fast as he wanted, he would throw temper tanturm, bite into the fabric and throw it on the floor, then throwing other things running all over...

anyway he is rarely if ever sick. his teeth are perfect. no cavity! (and he cracks pecans with his teeth!)
but his hands are shaking (guess its medication side affects) He used to be on ritalin in his childhood.

now he is age 27 (twenty seven). is it too late to help him? what tests shall be done to him? whom shall we contact for these tests? and what help can be done?
phone numbers of real people to contact will be greatly appreciated! also if there are anyone who was in that condition and got better, we would like to contat them for testimony

we live in Brooklyn, New York

any idea will be appreciated!

sara